The implantation of Transcatheter Aortic Valve Replacement (TAVR) devices and Transcatheter Mitral Valve Replacement (TMVR) devices has provided significant opportunity for improved health for those patients that are too sick to undergo surgical valve replacement or those who are of significant age of which the trauma associated with surgical replacement does not merit the potential benefits of surgical replacement over transcatheter valve replacement. Although improvements are continuously being made in the TAVR and MTVR devices and their procedures, the presence of leakage of blood across the transcatheter valve in a retrograde direction has raised clinical concerns including the potential increased mortality due to such perivalvular leakage. Such blood leakage is also found with the use of standard surgical valve in the aortic and mitral positions. Occlusion devices have been used to block perivalvular leaks that occur following the implantation of surgical and transcatheter aortic and mitral valves however the occlusion devices can themselves cause problems to occur. These devices are not optimally designed for blockage of the thin, oval, crescent-shaped opening that occurs in perivalvular leaks. A typical standard occlusion device often will have a circular cross section and is not specifically intended to undergo a shape change during expansion that will fill the voids found in a channel that has an oval or crescent-shaped cross section. Also, the current occlusion devices typically have flanges on either end of the device to prevent such devices from migrating; these flanges tend to interfere with valvular function and with blood flow through the valve. What is needed is an occlusion device that conforms to a thin, crescent-shaped opening, blocks blood flow through such opening, cannot migrate, and does not interfere with valvular function and blood flow through the valve.